Organic electronic devices have attracted increased attention in recent years. An example of an organic electronic device includes an organic light emitting diode (OLED). Organic light emitting diodes are promising for a range of applications due to their high power conversion efficiency and low processing costs.
Organic electronic devices may be constructed by depositing a layered structure on a transparent substrate. The layered structure includes a transparent anode layer, at least one active organic layer, and an opaque cathode layer. In this approach, the active organic layer emits or receives radiation through the transparent anode layer and substrate at the bottom of the device, and also may emit from both sides, or on either side (top or bottom) of the device. However, the substrate may contain embedded electrical components, such as pixel drivers and bus lines that reduce the light-emitting or light-receiving area.
Organic electronic devices may also be constructed by depositing a layered structure on a substrate, including an anode layer, at least one active organic layer, and a transparent cathode layer. In this approach, the active organic layer emits or receives radiation through the transparent cathode layer at the top of the device. The emitting or receiving area of this type of organic electronic device is not affected by electrical components embedded within the substrate as described above. In addition, opaque materials may be used to form the substrate. However, materials suitable for construction of the transparent cathode layer may not provide good electron-injection properties for all types of active organic material. Consequently, overall performance of this type of organic electronic device may be adversely affected. Cathode layer materials that provide good electron-injection properties may also be highly reactive in ambient conditions. Accordingly, these materials require encapsulation which may in turn reduce light emission or reception through the cathode layer, and may adversely affect overall performance of this type of organic electronic device.
Organic electronic devices may be constructed by depositing a layered structure on a substrate, including a cathode layer, at least one active organic layer, and a transparent anode layer. In this approach, the active organic layer emits or receives radiation through the transparent anode layer at the top of the device. Cathode layer materials that provide good electron-injection properties may be highly reactive in ambient conditions, or may be highly reactive or incompatible with certain substrate or circuitry contact materials, or with certain processing methods. Accordingly, incorporation of these cathode layer materials into the device at an early fabrication stage may thus increase the complexity and cost of the fabrication process.
There remains a need for an organic electronic device with a light emitting or light-receiving area that remains unaffected by electrical components embedded within the substrate, and that utilizes cathode layer materials which provide suitable electron-injecting properties and are relatively easy to incorporate into the fabrication process.